Field measurements and computer-based predictions suggest
that the magnitudes of seasonal peak snowpack water equivalents
are becoming less and the timing of these peaks is occurring
earlier in the snowmelt-runoff season of the western United States.
These changes in peak snowpack conditions have often been attributed
to a warming of the regional climate. To determine if these changes
are also occurring in Arizona, almost 75 years of water equivalent
measurements on snow courses maintained by the U.S. Natural Resources
Conservation Service and their cooperators have been analyzed
in a preliminary study of possible effects of recent climatic
change. The results of this analysis agree generally with the
findings of other studies in the Western states.